CMMG 16 Inch 22 Long Rifle CM, M4, RGB, RKM7 Upper Receiver features a W.A.S.P. Treated Barrel (Weapon Armament Surface Protection). W.A.S.P. is a salt bath ferritic nitrocarburizing surface conversion process or more commonly referred to as nitriding. The nitriding conversion is applied to the barrel inside and out, along with the front sight base on our LE rifles and uppers. Nitriding offers improved wear, abrasion, and corrosion resistance when compared to hard chrome lining or phosphating.
Unlike chrome lining, where the chrome is built up on the surface, nitriding converts the surface without the risk of dimensional build up. CMMG Pioneered the use of this nitriding process on AR barrels and has been using it for many years.